Symmetric and asymmetric optical multi-peak solitons on a continuous wave background in the femtosecond regime

TL;DR

This paper investigates symmetric and asymmetric multi-peak optical solitons in femtosecond fiber systems, revealing their formation, stability, shape-changing interactions, and establishing a phase diagram linking various nonlinear excitations.

Contribution

It introduces a detailed analysis of multi-peak solitons, including their formation mechanism, stability, shape-changing behavior, and a phase diagram connecting different nonlinear wave phenomena.

Findings

Multi-peak solitons can be viewed as superpositions of periodic waves and single-peak solitons.

Stable propagation of symmetric and asymmetric multi-peak solitons is confirmed through simulations.

Shape-changing interactions occur in both soliton-soliton and soliton-breather collisions.

Abstract

We study symmetric and asymmetric optical multi-peak solitons on a continuous wave background in the femtosecond regime of a single-mode fiber. Key characteristics of such multi-peak solitons, as the formation mechanism, propagation stability, and shape-changing collisions, are revealed in detail. Our results show that this multi-peak (symmetric or asymmetric) mode could be regarded as a single pulse formed by a nonlinear superposition of a periodic wave and a single-peak (W-shaped or antidark) soliton. In particular, a phase diagram for different types of nonlinear excitations on a continuous wave background including breather, rogue wave, W-shaped soliton, antidark soliton, periodic wave, and multi-peak soliton is established based on the explicit link between exact nonlinear wave solution and modulation instability analysis. Numerical simulations are performed to confirm the propagation stability of the multi-peak solitons with symmetric and asymmetric structures. Further, we unveil a remarkable shape-changing feature of asymmetric multi-peak solitons. It is interesting that these shape-changing interactions occur not only in the intraspecific collision (soliton mutual collision) but also in the interspecific interaction (soliton-breather interaction). Our results demonstrate that each multi-peak soliton exhibits the coexistence of shape change and conservation of the localized energy of light pulse against the continuous wave background.